Hypertension

Question 1

What two things control blood pressure?

Answer 1

• Baroreceptor (and chemoreceptor)- short term

* RAS pathway –long term

Question 2

Briefly describe the baroreceptor reflex

Answer 2

• The baroreceptors are the pressure sensing bodies. They are also called stretch receptors
• At low pressures, baroreceptors become inactive.
• Decreased blood pressure decreases baroreflex activation and causes heart rate to increase and to restore blood pressure levels
• These baroreceptors are connected to the CNS’s autonomic nervous system

Question 3

What are risk factors for hypertension?

Answer 3

· Age: Increases as you age
· Men—middle age. Women— menopause
· Race: African, aborigines
· Family history
· Overweight or obese
· Physical Inactivity: High heart rate, tendency to develop hyperlipidemia, obesity
· Tobacco Smoking: Vasoconstriction, damage to blood vessels
· High salt (sodium) diet: Renin-angiotension pathway to retain fluid, increases BP
· Lack of potassium in diet: Ka exist in fruits and vegetables; lack of Ka leads to increase in Na
· Alcohol: Damage your heart, cardiac hypertrophy
· Stress: Increase corticoid steroid level, vasoconstriction

Question 4

What is hypoxia induced hypertension?

Answer 4

• High levels of CO2 activate chemoreceptors (receptors that measure oxygen and CO2 levels in arterial blood)
• This activates sympathetic effectors in the heart and peripheral vessels (vasoconstriction)
• This causes RAS pathway activation

Question 5

What are consequences of hypertension?

Answer 5

• Concentric Hypertrophy: Myocyte Width increases
• Eccentric Hypertrophy is increase in Myocyte Length
• Pre-load increase (dilation of the ventricle)
• Volume Overload (RAS activation due to reduced CO)
• Relative Ischaemia (Muscle and cells / Capillary Mismatch)
• Scar (fibrotic) in the infarct zone
• Reduced Systolic Function (contractility decrease)
• Mitral Regurgitation

Question 6

What are causes for congestive heart failure?

Answer 6

Left side:
Oxygenated blood from lungs
• Ischaemic Heart Disease 
• Systemic Hypertension 
• Mitral or Aortic Valve Disease 
• Primary Disease of Myocardium 

Right side:
Deoxygenated blood to lungs
• Left Ventricular Failure 
• Lung Disease  
• Pulmonic or Tricuspid Valve Disease